The booby traps waiting for Boris

In the City Hall chamber late on Friday night, moments before the Mayoral result was declared, one of Ken Livingstone's most senior aides sat in the front row of the spectator seats, openly and paralytically drunk, his hair tousled, holding the rail in front of him for support. Another of the top team was crying. And Simon Fletcher, the ex-Mayor's chief of staff, looked like he was about to die.

These were the people who have run London for the past eight years, people not just defeated but visibly stunned by their defeat. Until the very final hours, Team Ken had viewed their challenger, Boris Johnson, as not just wrong but somehow illegitimate and his election as inconceivable.

Those in that very top layer have gone now. But as Boris Johnson starts his first working day as Mayor, many of his remaining staff share the same mindset. Working with a potentially uncomprehending, even hostile bureaucracy - some of whom may try to re-fight the election in the City Hall corridors - is just one of the issues Johnson and his new team must tackle if they are to succeed.

"The staff who have been in over the weekend have been great and extremely helpful," says one senior Boris aide. "But there will need to be changes." Yesterday, they finalised a few of their first appointments. Sir Simon Milton, the Westminster Council leader, will advise on housing and planning - Westminster is known for its opposition to ever-higher towers. Dan Ritterband, the highly-rated campaign director, will be head of marketing. Kit Malthouse, a new Tory member of the London Assembly, will take a policing role.

There will be a full forensic audit of the GLA to find out what has been spent, what has been wasted and where " the kittens need to be drowned", as one insider put it. And yesterday the new regime was already removing walls and partitions on the eighth floor of City Hall, the Mayor's floor. "He's got to be open to the staff - no more cliques," said one.

But other, invisible barriers stand in the new Mayor's way. He may have a huge personal mandate - the third biggest in Europe, after the presidents of France and Portugal - along with great prestige and media attention. He may sit on the board of the Olympics. He and his agencies may have a turnover of around £11 billion a year. One thing the Mayor doesn't actually have all that much of, however, is power.

Most of the £11 billion comes from Whitehall, through grants; most of the rest from bus and Tube fares. Less than a tenth of it comes from the council tax, the only source of revenue under the Mayor's direct control.

He has considerable power over the buses, and in planning, where he can overrule any borough council and block or approve any project deemed "strategic." But on the Tube he is still tied by the PPP. And over most other issues he is a facilitator or an influencer, rather than a decider.

"Their key tasks are to get expectations in line with what they can deliver, and also to get what Gordon Brown hasn't got: a narrative, a story about what they are trying to do," says Tony Travers, the London government expert at the LSE. "The great advantage is that thanks to his opponents talking him down, Boris comes in with low expectations."

In policing, the issue at the heart of Boris's campaign, his powers are far more limited than most people imagine. He cannot tell the Met what to do or what crimes to prioritise - those are "operational matters" for the Commissioner, Sir Ian Blair. The Mayor's Metropolitan Police Authority does set the Met's budget, does appoint its senior ranks, and could, in theory, dismiss Sir Ian. In practice, however, it is one of those bodies, like the London Assembly, set up to provide the appearance of local democratic control, rather than the reality. Most of its actions are effectively subject to the veto of the Home Secretary. Though Boris will chair the MPA, he can appoint only 12 of its 23 members - and many of those 12 will have to be his political opponents.

Wearing a slightly forced smile, Sir Ian, who has provided service beyond the call of duty to New Labour, was on hand to greet his new Tory Mayor at a press conference on Saturday. As Boris stressed the need for change in crime policy, the Commissioner told Sky News of the need for "continuity". Whether this was actually a deliberate challenge to Johnson, or merely an example of Sir Ian's legendary political ineptitude, remains to be seen.

OVER the Stockwell shooting fiasco, the Tories called for Sir Ian's resignation. Boris did, too, though much less emphatically. Team Johnson members are cagey about the Commissioner's future but experts think it would be "silly" of them to pick a fight that they might not win. "Better to live with Ian Blair, which it looks to me as if they're going to," says Travers.

What Boris can do in policing is what he can do in most other things, which is exercise influence, wield the considerable moral power of his 1.1 million votes, and use budget allocations to adjust the tiller. Whether that makes much difference to kids killing each other, only time will tell.

Johnson has more power over the other uneasy-looking characters at that press conference, Manny Lewis, chief executive of the LDA, and Peter Hendy, head of TfL and the man who gave Mr Livingstone his most totemic vote-loser, the bendy bus. Even before the election, Hendy was lobbying hard to keep his £320,000-a-year job.

But his case was harmed by emails leaked to the Standard during the campaign-in which this supposedly neutral civil servant made clear his political sympathies, asking Mr Fletcher, Livingstone's chief of staff: "Is there mileage now or later in refuting Boris's two public transport ideas - artics [bendy buses] cause death ... and Routemasters are good?" He worried that bendy bus incidents "look as if they are meat to BJ's [Johnson's] campaign". Dismissing a London Lib-Dem MP, he said: "Pity the Lib-Dems are more Tory than Labour!"

Since the election, "Hendy has been bending over backwards to help us", said one Johnson aide. "He has studied our pledges and came in to his meeting with a document on how they could be achieved." Hendy is expected to be kept for the next few months, partly because some of his potential replacements are asking to be paid too much.

With his feet still under the desk, Hendy could cling on. But given his opposition to a key plank of Mayoral policy, it is not intended that the Transport Commissioner will have a future beyond the summer. Hendy's expertise is also in buses, and the real transport nightmare facing Boris is on the railways, with Metronet and above all Crossrail, where TfL's share amounts to more than £7 billion and he will need the best talent he can find - at any price - to prevent the project bleeding London dry.

Some Tories are concerned that Boris, one of whose traits is a desire to be liked, will not be tough enough with the staff. For Hendy is only the most senior example of how City Hall's servicedelivery functions have been politicised. As Mr Livingstone himself agreed, the GLA is a "personal fiefdom"-set up in the image of the only Mayor it has ever known, himself. Many of its staff are, of course, professional and impartial. But the sympathies of others could be gauged on Friday night at a pub near City Hall called the Woolpack.

As it became increasingly clear that Livingstone had lost, dozens of staff gathered at the Woolpack to drink deep draughts of bitter towards Johnson, the Evening Standard, the "Tory suburbs" and all the other forces that supposedly cost Labour the mayoralty. As I entered the pub's crowded garden together with the Mayor's former Asian affairs adviser, now anti-Ken whistleblower, Atma Singh, we were shouted at and told to "get out" by a group of people who, according to Mr Singh, included serving GLA officers.

Such small fry can be relatively easily dealt with, if the new Mayor wants to. "After the election I had 825 text messages from people saying they always knew Boris would do it, and here's my CV," says one amused Johnson staffer. But what of that rather more important enemy, Her Majesty's Government? A successful Boris mayoralty is the last thing Gordon Brown wants - and since he holds the purse-strings, the potential for sabotage seems clear.

The area of greatest danger is probably, once again, Crossrail. "I'm not convinced Crossrail is fundable and I wonder whether Whitehall could manoeuvre Boris into a situation where he gets the blame for the collapse of Crossrail," says Travers.

On the whole, though, the outlook for Boris is fair. Much of the GLA's funding has now been agreed for several years ahead. It could be changed, but Travers thinks Brown would suffer if he was seen to punish London for voting Tory. " The Government is completely trapped," he says. "Labour have got so many marginal seats in London. Support for the GLA is not like government support for most local authorities. It's specific grants - they're much more difficult to fiddle without being noticed."

Yesterday one of Labour's most respected MPs, Jon Cruddas, praised Johnson's "emotional literacy" and ability to "connect with people". In the Mayoralty, as Ken Livingstone showed, even relatively small, symbolic acts can go a long way, for good or ill. A big personality makes the job seem more substantial than it is.

And one key piece of advice is something that Boris should not have too much trouble with. "Boris should go down the route of the mayor of New York, Michael Bloomberg," says Tony Travers. "He gets people to do things by epic gentility and kindness." Not like Ken, is the unspoken message.